Pump or motor for power transmissions



Nov. 14, 1950' F. T. HARRINGTON 2,530,242

PUMP OR MOTOR FOR POWER TRANSMISSIONS Filed Nov. 16, 1945 3 Sheets-Sheet1 IN V EN TOR. Fees 7. ffiaqzvz rom NOV. 1950 F. 'r. HARRINGTON2,530,242

PUMP 0R MOTOR FOR POWER TRANSMISSIONS Filed Nov. 16, 1945 3 Sheets-Sheet2 INVEN TOR. 7755515 I 1%FF/N5'TUN BY (Q fir ram/5."

Nov. 14, 1950 F. T. HARRINGTON 2,530,242

PUMP OR MOTOR FOR POWER TRANSMISSIONS Filed Nov. 16, 1945 3 Sheets-$heet3 100 i L I05 II J J h 1,1 IO 6 27 n -|o2 59 FIG. 5

1 IL I) 55 I "a T O fi LEE-7' 3|- ms I02 1' I05 I FIG.6

INVENTOR.

FERRIS T. HARRINGTON ATTORNEY Patented Nov. 14,1950

PUMP OR MOTOR FOR POWER TRANSMISSIONS Ferris '1. Harrington, Detroit,Mich, assignor to Vickers Incorporated, Detroit, Mich, a corporation ofMichigan Application November 16, 1945, Serial No. 629,039

7 Claims.

This invention relates to power transmissions,

particularly to those of the type comprising two or more fluid pressureenergy translating devices, one of which may function as a pump andanother as a fluid motor.

The invention relates specifically to a pressureoperated, volumetriccontrol device for use with fluid prnps and motors of the axial pistontype having a swinging yoke for varying the disthe case temperature fromincreasing excessively when the device operates for long periods of timein the neutral position.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred form of the present invention is clearlyshown.

In the drawings:

placement of the device. In pumps of this gen- 1. Figure 1 is asectional view of a fluid energy eral class, the pumping action iscreated by pistons reciprocating within bores of a cylinder block, theangle of which with respect to the drive shaft may be changed byswinging the yoke.

translating device incorporating a preferred form of the presentinvention.

Figure 2 is a plan view of a portion of the invention shown in Figures 1and 3.

As the angle of the cylinder block with respect Figure 3 is a viewsimilar to that of Figure 1 to the drive shaft is decreased, the lengthof stroke of the pistons is decreased, resulting in a relativelydiminished volumetric output. If theyokeis. swung to the completelyneutral posibut showing the parts of the invention in a differentposition.

Figure 4 is a plan view of a portion of the invention shown in Figures 1and 3.

tion, the cylinder block will be in axial alignment Figure 5 is apartial sectional view taken on with the drive shaft, and, although therotation of the block continues, there is no relative motion between thepistons and the valve block, and the output becomes zero.

It has hen the practice in the past to provide pressure-operated,volumetric control mechani'sms with variable displacement devices ofthis generalclass which serve the purpose of maintaining pressure withina predetermined range, but varying the volume of fluid as required'bythe hydraulic system. In some applications the pump may be required tooperate for long periods at zero displacement and full pressure whichmay, because of the heavy loading of the bearings and other parts, causeoverheating of the pump mechanism unless special provisions are made tocool the pump casing or the fluid in it.

It is an object of the present invention to provide an improvedpressure-operated, volumetric "control device for use with pumps andmotors of the general class mentioned.

It is also an object of this invention to provide for this general classof fluid devices an improved pressure-controlled,volumetric controlmechanism which is capable of automatically diminishing volumetricoutput to practically zero while, at the same time, maintainingth"e-.pressure at a predetermined, constantly regulated value.

:It is also an object of this invention to provide ansimprovedpressure-operated, volumetric control mechanism which, while reducingvolumetric output to practically zero, will not only maintain maximumpressure in the system but which is provided with a novel means forpreventin line 5-5 of Figure 1.

Figure 6 is a partial sectional view taken on line 6-6 of Figure 1.

Referring now to Figure 1, there is shown a pump of the axial pistontype having a casing member In in which is journalled a main drive shaftI2 having a flange l4. Connected to the flange M in sockets, not shown,are a plurality of piston rods [6 having pistons it at their oppositeends shiftable within bores 19 of a cylinder barrel 2!! which isconnected to the drive shaft II for rotation thereof in the well-knownmanner.

The cylinder barrel 20 is adapted to rotate against a valve plate 22rigidly connected to a swinging yoke 24, the latter being pivotallyconnected within the casing member H) by means 01 a suitable pintleconstruction 26. As the cylinder barrel 20 rotates, the piston it willcooperate with ports in the valve plate which are connected to inlet andoutlet passages, within the casing member ill, so as to take in fluidfrom the inlet passage on the suction stroke and force fluid out throughan outlet passage and an outlet connection 21 on the pressure stroke ofsaid pistons.

Thus, as shown in Figures 5 and 6, the casing I0 is provided withduplicate passages 29 and 3|, the former of which is connected to aninlet connection 33 and the latter of which is connected to the outletconnection 21. Each pintle assembly 26 is provided with a plurality ofports 35 with which the inlet and outlet casing passages 29 and 3| areadapted to register.

Likewise, the yoke arms are provided with duplicate passages 31 whichregister with another set of .ports 39 provided in the pintle assemblies26. Only on'eot the yokearm passages 31 is shown in Figure '5 which-isadapted-to serve as an inlet passage through which fluid 'flows from theupper pintleassembly to one of duplicate ports 43 in the valve plate 22.One of the ports 43 is connected to an arcuate inlet port 45 in thevalve plate 22 while an arcuate outlet port 41 in the valve plate 22 isconnected to a duplicate of the port 43, not shown. The latter port isconnected by a duplicate of the yoke arm passage 31 to the ports 39 ofthe opposite pintle assembly 26. The valve plate inlet and outlet ports45 and 41 cooperate with ports formed at the end of the piston bores I9on the suction and pressure stroke of the pistons.

The interior of the casing I0 may be bled by means of a conduit 53connected to a drain port 54 of the casing member I0 and to a tank 55.The tank 55 is connected to the inlet connection 33 by a conduit 51. Apressure delivery conduit 59 is connected to the outlet connection 21and is adapted to be connected to the power side of the transmission,not shown, in the conventional manner.

Mounted on the casing member I0 is a pressure control housin 28 withinwhich is shiftably mounted a pressure control valve 30 for the purposeof limiting the maximum pressure of the pumping device and controllingthe admittance of pressure fluid to an actuating piston 32. Piston 32,the closed end of which is linked to yoke 24, is shiftably mounted upona piston guide 34 which is connected to housing 28 and extends into theinterior of easing I0. Piston guide 34 has a longitudinal'steppedpassage 36 intersecting a longitudinal bore 38 of housing 28 which iscontrolled by valve 30 in such a manner as to normally blockcommunication between the discharge side of the pumping device andpassage 36, the latter oi which leads directly to the closed end ofpiston 32. A hollow cylinder 40 having a plurality of elongated ports 4|surrounds piston 32 within casing member I0 so that a chamber 42 isformed therein and is rigidly mounted within a bore 44 of casing memberI0 so that a flange 46 of cylinder 40 abuts a shoulder 48 of bore 44. Aspring 49 mounted within chamber 42 abuts a flange 50 of piston 32biasing the piston 32 to one limit 01' its travel and setting theoriginal maximum angle of yoke 24 for maximum output of the pumpingdevice. A transverse passage 52 in guide portion 34 which intersectspassage 36 is normally blocked from communication with chamber 42, andconsequently the interior of casing member I0, by piston 32. Transversepassage 52 is so placed that upon the control valve 30 admittingpressure fluid to piston 32 the latter will have to shift yoke 24 almostto the neutral position before flange 50 will break over the passage 52.

It should be noted that transverse passage 52 may be so placed in guideportion 34 so that the angle of the yoke 24 may be reduced to any anglebetween maximum and zero so as to limit the minimum output of thepumping device to the volume desired.

As is more clearly shown in Figure 4 valve 30 is shiftable within ahollow sleeve 56 provided with tear drop shaped ports 58 in alignmentwith a groove 60 and ports 62 spaced apart from ports 58 in alignmentwith a groove '64. Sleeve 56 is inserted in bore 38 of housing 28 sothat a flange 66 of said sleeve abuts a shoulder 68 of bore 38 and sothat groove 60 registers with and overlays passage 36 and groove g 64registers with and overlays a passage in housing 28 connecting chamber42 to bore 38.

Control valve 30' consl'stsof apiston I2 prowided with spacedapart'lands I4, 16, I8 and00.

Lands'TI-"and I6 control the admission of pressure fluid to passage 36.Land I8 and control passage I0 permitting fluid to escape from piston 32upon valve 30 shifting back to its original position when pressuredecreases below the setting of valve 30. Piston I2 is provided with ahead 82 which is partially rounded so as to rest properly against a seat84 formed in a shift able seat and spring retainer member 86. A spring88 placed within the left end of bore 38 abutting retainer 66 determinesthe maximum pressure attainable by the pumping device and normallybiases valve 30 so that land 16 blocks port 58 of sleeve 56 fromcommunication with passage 36. An adjustable screw 90 abuts the left endof spring 88 and closes the left end of bore 38. Valve 30 is adapted tobe limited in its rightward movement by a portion 92 of a closure member94 which extends into bore 38, the latter closing the right end of bore38.

Portion 92 being smaller in diameter than that of bore 38 a chamber 96is formed in the right end of bore 38 between closure member 94 and theright end of sleeve 56. A passage 98 in housing 28 intersects chamber96. A passage I00 intersectin a passage I02 which connects to the outletpassage 3|, by means of a passage I03 (Figure 6), registers with passage98 so as to place chamber 96 in communication with the discharge side ofthe pumping device. The terminus of the passage I03 opening to theexterior of the casing I0 is closed by a suitable plug I05. Portion 92is provided with a longitudinal passage |04 which intersects atransverse passage I06 in communication with chamber 96 providing ameans of communication between the right end of valve 30 and thedischarge side of the pumping device.

Land I4 of valve 30 is provided with a plurality of notches I08 whichpermits pressure fluid entering chamber 96 to be metered into tear dropports 58 into passage 36 through the medium of said notches as land I6breaks over ports 58. A diagonally drilled passageway I I0 connects theleft end of bore 38 with passage I0 in order to take care of the fluiddisplacement caused by leftward shifting of valve 30 into said bore.

In operation, with the pump running and the angle of the yoke 24 asshown in Figure 1 the volumetric output of the pump is at maximum value.Pressure fluid which is discharging through outlet connection v2I actsagainst the right end of valve 30 by means of passage I03 connected tothe outlet passage 3|, passage I02, passage I00, housing passage 98,chamber 96, transverse passage I06 and longitudinal passage I04 inportion 92. Pressure fluid in chamber 96 is prevented from enteringpassage 36 through the medium of notches I08 and tear drop ports 58 byland I6 of valve 30. This predetermined volumetric output will continueuntil the pressure in the system reaches a point high enough to overcomethe resistance of spring 88 when valve 30 will begin to shift to theleft. A the left end of piston 30 shifts through sleeve 56 into the bore38 the slight quantity of fluid displaced thereby may flow into passageI0 by means of passage H0 and to drain port 54 by means of chamber 42and cylinder ports 4|. As land I6 breaks over ports 58 pressure fluidwill begin to h a bemetered through notches I33 into ports l3 throughgrooves I to passage 36 and by means of passage 33 to the closed end ofpiston 32. As land It continues to break over ports 58 a graduallyincreasing amount of fluid entering passage 30 will continue to shiftpiston 33 against the reslstance offered by spring 49 to change theangle of yoke 34, shortening the length of stroke of pistons i3 anddecreasing the volumetric output of the pumping device. Piston 32 willcontinue to shift until the flange portion 53 thereof breaks overtransverse passage 32 in guide portion 34.

As shown in Figure 3 the complete output of the pump, which is nownearly zero because of the angle of the cylinder barrel in relation tothe drive shaft. is now by-passed into the interior of the casing memberII by means of passage I3, chamber 42 and ports 4|. From the interior ofthe casing it this fluid may bleed out of drain port 84 to the tank 55by means of the conduit 83.

When the pressure in the system decreases to a point below theresistance of spring 33 control valve 30 will be shifted rightwardly bytheforce of said spring. At the point that flange 33 of piston 32 closestransverse passage 82 and land 16 of valve 30 blocks ports I! of sleeveI! from the discharge side of the pump, land II. no longer blockscommunication between ports '3 and ports 64. Trapped fluid in piston 32and passage 38 may then escape to the interior of the casing ill inorder to allow piston 32 to shift by the force of spring 48 to theposition shown in Figure l. Fluid escapes from piston 32 through passage36, groove I of sleeve 58, ports I8, and is guided by lands I3 and 30 ofvalve 30 to ports 02 and by means of groove Q4 of sleeve 56, passage 10,chamber 42, and ports 4! and cylinder 40 to the interior of the casingfrom where it is discharged through drain port 54. When piston 32 hasshifted completely the angle of yoke 24 is as shown in Figure 1 and thevolumetric output of the pump is again at maximum value.

It should be noted that when the maximum pressure in the system asdetermined by spring 30 has been reached and control valve 30 hasshifted sufllciently so as to permit fluid to enter passage 34 to shiftpiston 32, that the volumetric output of the device will be practicallyzero. Due to the fact that this small output is bled into casing I l andfrom casing it back to the tank It by means of drain port 84 and conduit51, the heat created by such operation will be practically nil.

It should also be noted that the transverse passage I! may be placed inpiston guide 34 relative to the cracking point of the flange portion IQof piston 33 so that the minimum volumetric output of the pumping devicemay be regulated to supply Just the right amount of minimum outputnecessary to maintain the desired pressure in the system or to flt theminimum needs of any installation.

It should also be noted that the invention is adaptable to be used withpractically any fluid energy translating device having a swinging yokefor varying the displacement of the device simply by connecting thedischarge side of the device to passage 93 of housing 28 and so thatports 4| of cylinder 40 are in communication with the interior of thecasing member.

While the form of embodiment of the invention as herein disclosedconstitutes a preferred form, it is to be understood that other forms 6might be adopted, all coming within the the claims which follow.

What is claimed is as follows:

1. A fluid energy translating device of the variable displacement typecomprising in combination a casing having high and low pressureterminals, a shiftable member for varying the displacement of the deviceand a discharge outlet for circulation of a small flow of fluid forcooling purposes, a volume control mechanism comprising pressureresponsive actuating means connected to the member for shifting the sameand having an expansible pressure chamber in communication with the highpressure terminal of the device, and means forming a by-pass passagehydraulically connected to said chamber and controlled by the actuatingmeans, said by-pass passage being connected to said discharge outletthrough the interior of the casing and being opened and closed by theactuating means at predetermined points within its range of movement. v

2. A fluid energy translating device of the variable displacement typecomprising in combination a casing having high and low pressureterminals, a shiftable member for varying the displacement of the deviceand a discharge outlet for circulation of a small flow of fluid forcooling purposes, a volume control mechanism comprising pressureresponsive actuating means connected to the member for shifting thesame, and having an expansible pressure chamber in communication withthe high pressure terminal of the device, means forming a by-passpassage hydraulically connected to said chamber and controlled by theactuating means, and means resiliently biasing the actuating means toone limit of its travel and closing the by-pass passage, said by-passpassage being connected to said discharge outlet through the interior ofthe casing and being opened by the actuating means in response toincreases of pressure at a predetermined point within its range ofmovement.

3. A fluid energy translating device of the variable displacement typecomprising in combination a casing having high and low pressureterminals, a shiftable member for varying the displacement of the deviceand a discharge outlet for circulation of a small flow of fluid forcooling purposes. a volume control mechanism comprising pressureresponsive actuating means mechanically connected to the member forshifting the same and having an expansible pressure chamber, valve meanshydraulically connected to the expansible chamber and to the highpressure terminal of the device for connecting and disconnecting thehigh pressure terminal from scope of the expansible pressure chamber,and means forming a by-pass passage hydraulically connected to theexpansible chamber and controlled by the actuating means, said by-passpassage being connected to the discharge port through the interior ofthe casing and being opened and closed by the actuating means atpredetermined points within its range of movement.

4. A fluid energy translating device of the variable displacement typecomprising in combination a casing having high and low pressureterminals, a shiftable member for varying the displacement of the deviceand a discharge outlet for circulation of a small flow of fluid forcooling purposes, a volume control mechanism comprising pressureresponsive actuating means mechanically connected to the member forshifting the same and having an expansible pressure chamber, valve meanshydraulically connected to the expansible chamber and to the highpressure terminal for connecting and disconnecting the high pressureterminal from the expansible chamber, means forming a by-pass passagehydraulically connected to said chamber and controlled by the actuatingmeans, and resilient means biasing the actuating means to one limit ofits range of travel and closing the by-pass passage, said by-passpassage being connected to the discharge outlet through the interior ofthe casing and being opened and closed by the actuating means atpredetermined points within its range of movement.

5. A fluid energy translating device of the variable displacement typecomprisin in combination a casing having high and low pressureterminals, a shiftable member for varying the displacement of the deviceand a discharge outlet for circulation of a small flow of fluid forcooling purposes, pressure responsive actuating means connected to saidmember for shifting the same and having an expansible pressure chamberhydraulically connected to the outlet, and means forming a by-passpassage hydraulically connected to the chamber and to the interior ofthe casing and controlled by the actuating means, said actuating meansnormally closing the passage and opening the passage in response topredetermined increases of pressure at the outlet within its range ofmovement whereby when the device is operating at small displacement, asmall fluid circulation may be established through the casing forcooling purposes.

6. A fluid energy translating device of the variable displacement typecomprising in combination, a casing member havin an inlet and an outlet,a shiftable member for varying the displacement of the device and aseparate discharge port leading from the interior of the casing,pressure responsive actuating means connected to said member forshifting the same and having an expansible pressure chamber incommunication with the outlet, means forming a by-pass passagehydraulically connected to the pressure chamber and to the interior ofthe casing and controlled by the actuating means, said actuating meansnormally closing the passage and opening the passage in response topredetermined increases of pressure at the outlet within its range ofmovement whereby when the device is operating at small displacement asmall fluid circulation may be established through the casing forcooling purposes, and means for supplying fresh cooled fluid to theinlet of the device.

7. A fluid energy translating device of the variable displacement typecomprising in combination a casing member having an inlet and an outlet,a shiftable member for varying the displacement of the device, and aseparate discharge port leading from the interior of the casing,pressure responsive actuating means connected to said member forshifting the same and having an expansible pressure chamberhydraulically connected to the outlet, means formin a by-pass passagehydraulically connected to the actuating means and to the interior ofthe casing and controlled by the actuating means, said actuating meansnormally closing the passage and opening the passage in response topredetermined increases of pressure at the outlet within its range ofmovement, and a casing fluid circulating and cooling circuit including afluid supply source connected to the inlet of the device, and a conduitconnecting the separate discharge port to the fluid supply sourcewhereby when the device is operating at small displacement a small fluidcirculation may be established through the casing for cooling purposes,and the device is continually supplied with fresh cooled fluid.

FERRIS T. HARRINGTON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,087,772 Bempthorne July 20,1937 2,140,633 Kooks Dec. 20, 1938 2,177,098 Doe et a1. Oct. 24, 19392,284,109 Vickers May 26, 1942 2,284,897 Harrington June 2, 19422,303,955 Rose Dec. 1, 1942 2,403,371 Ifleld July 2, 1946 2,429,403Deschamps Oct. 21, 1947 2,433,222 Huber Dec. 23, 1947

